#include <stdio.h>
int main() {
    int sum = 0;
    int sign = 1;

    for(int i = 1; i <= 101; i += 4) {
        sum += i * sign;
        if(i + 2 <= 101) {
            sum += (i + 2) * (-sign);
        }
        sign = -sign;
    }

    printf("The sum of the series is: %d\n", sum);
    return 0;
}